International Panel Revises NMOSD Diagnostic Criteria Based on Evidence-Based Consensus

At the 2025 European Committee for Treatment and Research in Multiple Sclerosis (ECTRIMS) Congress, held September 24-26, in Barcelona, Spain, the International Panel for Neuromyelitis Optica Diagnosis (IPND) presented new evidence-based diagnostic criteria and updated nomenclature for neuromyelitis optica spectrum disorder (NMOSD). The latest framework distinguished aquaporin-4 antibody–positive (AQP4-IgG+) NMOSD as a distinct disease and reclassified related seronegative conditions as separate syndromes.¹

The panel, a steering committee of 26 members and 60 special advisors as well as consensus faculty, conducted a comprehensive review of data published since the last published consensus guidelines in 2015.² Using a systematic literature approach and a modified Delphi consensus process, experts revised criteria for diagnosing AQP4-IgG+ NMOSD and clarified guidance on testing and interpretation of aquaporin-4 antibodies. Prior literature underscored differences in the biology and presentation of AQP4-IgG+ disease compared with myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) and other seronegative conditions.

Presented by lead author Dean M. Wingerchuk, MD, director of the Division of Multiple Sclerosis and Autoimmune Neurology at Mayo Clinic, the updated recommendations emphasized the use of MRI and visual system imaging to improve diagnostic accuracy. Experts also highlighted the need to standardize AQP4-IgG antibody testing, including the selection of assay type and appropriate timing for evaluation. Notably, the panel endorsed the use of the term “disease” specifically for AQP4-IgG+ NMOSD, reflecting growing evidence that this group has a distinct pathobiological basis.

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The revision process of the criteria brought together 6 focus areas, each comprising 8 to 18 experts, to address key aspects of NMOSD diagnosis. In the first 4 focus groups, experts concentrated on refining diagnostic criteria for patients with AQP4-IgG+ NMOSD whereas the 2 last groups assessed nomenclature for patients who tested negative for both AQP4-IgG and MOG-IgG antibodies. In addition to revisions of the diagnostic criteria, the IPND presented a proposed roadmap at ECTRIMS 2025 for the broader classification of central nervous system inflammatory demyelinating diseases.

In the evidence reviewed by the panel for the revised criteria, findings showed that AQP4-IgG+ NMOSD, MOGAD, and double-seronegative syndromes were unlikely to share identical disease mechanisms. Although patients may present with overlapping clinical features, the underlying biology differs, suggesting the need for tailored diagnostic and treatment strategies. The experts concluded that individuals with AQP4-IgG+ antibodies represent a well-defined disease entity, whereas seronegative cases may be better described as a group of related but distinct syndromes.

The panel also recommended specific parameters for AQP4-IgG testing to reduce misdiagnosis. Guidance included selecting validated assays, ensuring proper timing of testing relative to disease activity, and interpreting results alongside clinical and imaging findings. Enhanced MRI protocols, particularly of the optic nerves and spinal cord, were highlighted as potentially critical tools for distinguishing NMOSD from other inflammatory demyelinating disorders.

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REFERENCES
1. Wingerchuk DM, Marignier R, Palace J, et al. IPND 2025: Revised Consensus Criteria, Classification, and Nomenclature for Neuromyelitis Optica Spectrum Disorders. Presented at ECTRIMS Congress; September 24-26, 2025; Barcelona, Spain. Late-Breaking Abstract P427.
2. Wingerchuk DM, Banwell B, Bennett JL, et al. International consensus diagnostic criteria for neuromyelitis optica spectrum disorders. Neurology. 2015;85(2):177-189. doi:10.1212/WNL.0000000000001729